Objectives: A ssociations between well-being, serum levels of insulin-like growth factor 1 (IGF-I), and its primary binding protein IGFBP-3, were examined in an epidemiologic study. The influence of physical activity on the effect of hormones on well-being was considered.
Methods: Cross-sectional data from participants of the KORA-Age study (n=985, age 64-93) was analyzed in sex-specific multivariable regressions of well-being (World Health Organization (WHO) -5) or ill-being (geriatric depression scale (GDS) -15). Models were adjusted for age, physical activity, sleep, BMI, smoking, and cognition. Adjusted WHO-5 means demonstrated the interaction between hormone quintiles with physical activity.
Results: Full models indicated that increased IGFBP-3 positively associated with well-being in women (β estimate=0.14, standard error (SE)=0.06) and less so in men (β=0.11, SE=0.07). IGF-I associated positively with depression (β=0.11, SE=0.06) and negatively with well-being (β=-0.11, SE=0.06) in women. Similar but not statistically discernable effects were observed in men. Adjusted mean WHO-5 scores illustrated the positive effect of physical activity and IGFBP-3 on well-being in women only.
Conclusions: Opposite and independent associations of IGF-I and IGFBP-3 on well-being observed in women suggests neuroprotective effects of IGFBP-3 in age.
Keywords: Aging; IGF-1; IGFBP-3; Physical activity; Well-being.
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